Re: Loose Moose 2, AS39

And that's the key I guess. If you can provide enough tension on the halyard or tack and both are as close to the yard and boom respectively as possible AND the sail material can sustain these very high loads then you're in business. The Chinese sail material was weak and my sail material is also weak, being made of polytarp, so I've had to resort to battens to solve the sail billowing away from the mast problem.
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But the tack line is short and the halyard is tightened with a winch. The sail sets beautifully on all tacks.

222 sq' balanced lug main. None of the problems described. But the tack line is short and the halyard is tightened with a winch. The sail sets beautifully on all tacks. Sailing boat and boat there is no difference tack to tack to windward. Points as high as the cruiser/racers I have sailed against.
Eric

--- Inbolger@yahoogroups.com, "Rob Kellock" <creditscorenz@...> wrote:
>
> I noticed this as soon as I began using a balanced lug rig on my Michalak Philsboat, so borrowed Chinese Junk rig principles and used two horizontal flexible wooden battens across the reef points with fixed parrels around the mast. Problem solved.
> ========================================================================
> I have spent many hours sailing her since then and found she is more stable when on a starboard tack with the sail and boom pressing against the mast. On a port tack the boom wants to pull away from the mast and seems to provide more force pulling the boat over. Recently i have tied a loop around the boom and mast limiting the booms sideways movement allowing more reliable control without the leading edge of the sail moving in and out of the wind.
>

I noticed this as soon as I began using a balanced lug rig on my Michalak Philsboat, so borrowed Chinese Junk rig principles and used two horizontal flexible wooden battens across the reef points with fixed parrels around the mast. Problem solved.
========================================================================
I have spent many hours sailing her since then and found she is more stable when on a starboard tack with the sail and boom pressing against the mast. On a port tack the boom wants to pull away from the mast and seems to provide more force pulling the boat over. Recently i have tied a loop around the boom and mast limiting the booms sideways movement allowing more reliable control without the leading edge of the sail moving in and out of the wind.

And I'll add a couple of comments about water ballast myself.

Ballast is ballast.

Where volume does not matter feathers can be used. Water requires less volume than feathers. Center of gravity in a boat always matters and ballast is more effective the lower it is below the center of gravity. All else being equal, Gold and Uranium are the best ballast because by volume they weigh more than other things. All things are not equal. There are other considerations, cost being obvious. Lead is only a bit less dense and far cheaper than gold and uranium, and therefore it is widely used. Steel is fairly dense and less expensive than lead so it has also been widely used. Aluminium and concrete are about the same density so use concrete instead of aluminium which costs much more than cement. Rock was used in days of sail because it cost only labor, and could be sold as building stones or tossed overboard to take on paying cargo. Lead and steel work much better in a deep keel than lighter materials which might be used as ballast because they displace less water than lighter material allowing them to be placed lower, have less wetted surface, and have less floatation (all materials displace water and therefore have buoyancy). Rock, cement, and obviously water, don't work very well in deep keels.

Bolger popularised water. As interior ballast water can be used to good effect, especially in shallow hulls. It is not necessary for the chine to lift out of the water for the water ballast to be effective. Water is much bulkier than other ballast choices, but has the advantage of being readily available at no cost, and easily taken aboard and discarded. In a grounding, being able to discard ballast could save a boat. In a trailer boat water ballast can make the difference between using the family's small SUV instead of needing to acquire a half ton truck for towing (in the case of Martha Jane). I can tow ROGUE with a 3/4 ton Ford or Dodge pick up truck because part of the ballast is water so boat and trailer weight are <8,000 lbs on the road. The difference in cost of a 3/4 ton truck and a ton truck is considerable!!! The cost to me of using water ballast compared to lead is some lost storage space and some lost headroom in areas where it does not matter.

Round the world racers have used water ballast very effectively as shiftable ballast, and if I remember correctly, Tristan Jones last boat was a trimaran with shiftable water ballast in the amas (one ama to the other) to prevent capsize.

Martha Jane may not have been designed with enough ballast, and perhaps with other issues creating safety issues, but the use of water ballast is not the problem. A slightly larger water ballast tank would solve the problem if the problem were solely lack of ballast. (My understanding from previous posts on this list is that Martha Jane's problems have been solved with updated design changes making an already very good boat even better in my humble opinion.)

Eric

--- Inbolger@yahoogroups.com, "Peter" <pvanderwaart@...> wrote:
>
> > Now, as I understand things, water ballast, any ballast,
> > is unable to guarantee against knockdown,
> > but is merely meant to increase reserve stability,
> > AND meant in boats like MJ to help in their self-righting.
>
> I'm not familiar with all the cases you mention, but I do have a few comments.
>
> First, water ballast is very hard for people to understand. Most explanations that I have seen include some sort of conceptual error. Suffice it to say, it works best in light boats with hard chines and minimal deadrise.
>
> Second, the term reserve stability is generally used to refer to the volume of the hull and cabin (if any) that become submerged when the boat is knocked down, and which then supply buoyancy to right the boat. I think your use of the term as quoted above is a very minor error. The weight of the water ballast does make the reserve stability more effective by increasing the moment arm through which it works.
>
> Third, after one or two MJ incidents, and when inexpensive computer analysis tools had become available, PCB did stability studies of the MJ. I think this was after Suzanne joined him, but I'm not sure. He/they decided that MJ was too likely to flood by putting the cockpit rail underwater and designed some alterations with more flotation in that area in the form of sponsons. I believe there were other changes that increased the reserve stability as well.
>
> A design like MJ presents dilemmas. She's clearly much safer than the open oyster sharpies from which she is derived. She has a track record of miles sailed by many different owners, mostly without incident. On the other side of the coin, there have been a few times when an MJ has gotten into trouble. Perhaps we can say that the safety of the vessel is more dependent on the judgment and skill of the skipper and crew than is expected in 2010.
>
> Peter
>

> Now, as I understand things, water ballast, any ballast,
> is unable to guarantee against knockdown,
> but is merely meant to increase reserve stability,
> AND meant in boats like MJ to help in their self-righting.

I'm not familiar with all the cases you mention, but I do have a few comments.

First, water ballast is very hard for people to understand. Most explanations that I have seen include some sort of conceptual error. Suffice it to say, it works best in light boats with hard chines and minimal deadrise.

Second, the term reserve stability is generally used to refer to the volume of the hull and cabin (if any) that become submerged when the boat is knocked down, and which then supply buoyancy to right the boat. I think your use of the term as quoted above is a very minor error. The weight of the water ballast does make the reserve stability more effective by increasing the moment arm through which it works.

Third, after one or two MJ incidents, and when inexpensive computer analysis tools had become available, PCB did stability studies of the MJ. I think this was after Suzanne joined him, but I'm not sure. He/they decided that MJ was too likely to flood by putting the cockpit rail underwater and designed some alterations with more flotation in that area in the form of sponsons. I believe there were other changes that increased the reserve stability as well.

A design like MJ presents dilemmas. She's clearly much safer than the open oyster sharpies from which she is derived. She has a track record of miles sailed by many different owners, mostly without incident. On the other side of the coin, there have been a few times when an MJ has gotten into trouble. Perhaps we can say that the safety of the vessel is more dependent on the judgment and skill of the skipper and crew than is expected in 2010.

Peter

Is that your Martha Jane that Jim Michalak has written about recently? Written about how the box boats may, Martha Jane etc, go so fast and well?

Ironic in some ways, considering the boat he was observing from, the controversy preceeding... eghttp://groups.yahoo.com/group/bolger/message/11085

BTW, re "..The boat swamped because I had an unsecured offcenter hatch."http://groups.yahoo.com/group/bolger/message/2274Why did this data point apparently go entirely unnoticed back then? The poster wrote earlier that he had "the plans and I do not see that the builder deviated in any significant way from them, either in scantlings or leeboard weights or water tanks."http://groups.yahoo.com/group/bolger/message/2239

For starters the Martha Jane should have no off-centre hatches if built to plan! How then is it to be believed that the poster's boat did not deviate dangerously from plan in other highly significant ways? The controversy was about knockdowns. People got in a flap. Knockdowns that ended as capsizes. Flap, flap. Flooded hulls that couldn't right, that required rescue (and little wonder why!) Flap, flap, flap. MJ was attacked. Vehemently. It didn't stop there either.

MJ was elsewhere subjected to questionable "stability" "studies", was run down, criticised, mythologised, folk loricised, even elliotised. Was revised by PB&F...

Now, as I understand things, water ballast, any ballast, is unable to guarantee against knockdown, but is merely meant to increase reserve stability, AND meant in boats like MJ to help in their self-righting. This seems less likely to happen in boats that deviate from an excellent designer's plan, that deviate dangerously from ordinary, sensible, seaworthy design and operation. Off-centre hatch indeed! bah!! AFAIK, this point is very significant, and yet has slipped by in the bolgerverse unnoticed. I know of one Martha Jane original caught out in a very hard chance in Bass Straight, one of the worse places to be caught out in, that got knocked down, tossed down, yes, but recovered, recovered, recovered, and fetched her crew safely down wind unplanned a long way across to Tasmania! Yep, with centreline openings, covers secured.

Boy, oh boy, there is much said in that shorter old post linked to earlierhttp://groups.yahoo.com/group/bolger/message/11049

Graeme

--- Inbolger@yahoogroups.com, GBroadlick@... wrote:
>
>
> Bruce, i get a big kick out of your isometrics.
> thanks
>
>
>
>
>
>
> -----Original Message-----
> From: Bruce Hallman <hallman@...>
> To:bolger@yahoogroups.com
> Sent: Tue, Aug 17, 2010 1:57 pm
> Subject: [bolger] Loose Moose 2, AS39
>
>
>
>
> Bob Wise suggested I take a look at Loose Moose 2, Advanced Sharpie 39
> AS39 in Free!Ship Here are some isometrics plus the fbm file:
>
>http://www.hallman.org/bolger/AS39/
>

>http://www.hallman.org/bolger/AS39/

Very interesting. What a lot of work it must be.

I was looking at some Bolger drawings yesterday, and I got to wondering about Bolger's design methods. PCB was pretty open about the characteristics he wanted in a finished boat, but his final drawings were, for the most part, building plans with not too much info revealing the calculations and estimates that went into them. I don't remember a curve of areas anywhere, for example.

Bob Wise suggested I take a look at Loose Moose 2, Advanced Sharpie 39
AS39 in Free!Ship Here are some isometrics plus the fbm file:

http://www.hallman.org/bolger/AS39/